1. Technical Field
The subject matter of the invention is improvements in galvanization installations of metallic bands.
2. Background of Prior Art
It is known that in annealing or galvanization lines, a band, after having been subjected to an appropriate annealing cycle, is set in contact with melted zinc for the deposition of such metal on one or two faces. Generally, a galvanization installation comprises: a tank with a bath of melted zinc, one or several return rollers providing the guiding of the band to be galvanized along a path bringing it in contact with the metal of the bath, and means providing for the removal of excess metal and the drying of the band, in order to bring the thickness of the metal deposited to the desired value.
When the installation is provided for the galvanization of both faces of the band, the return roller or rollers are immersed in the tank and preferably positioned at the bottom of the tank so that the band dips into the bath of melted zinc.
For some applications, particularly automobile construction, it is required to provide sheets galvanized on a single face so as to obtain at the same time anti-corrosive properties inside the parts and surfaces solderable on the outer face. In such single face galvanization applications, the return roller or rollers are situated above the zinc bath level and the bath is placed in contact with the face of the sheet to be coated via various means, such as for example a lift due to the meniscus effect, an ebullition or again by using a coating roller partially dipping into the galvanization bath and coating with liquid zinc the required face of the band which is in contact with the bath. In this respect, reference is made to French Pat. No. 7619870 date June 30, 1976.
In consideration of the industrial needs for galvanized sheets, it is desirable to be able to carry out galvanization on one or both faces in the same installation. To this effect, various combinations of mechanical means can be considered, however such solutions require, generally, stopping the installation and changing the equipments, which brings about a significant loss of production capacity.